The present invention is directed to a treatment for wood and wood products that is water resistant, fire resistant, and includes a mold and pest inhibitor. More specifically, the present invention is a solution (and a powder mixture that may be used to form a solution) that may be applied to wood and wood products using pressure treatment techniques that are currently used in the wood treatment industry.
Typically, a treatment method includes the steps of placing the wood product into a pressure vessel and applying a vacuum, contacting the material with an aqueous solution and increasing the pressure in the pressure vessel, draining the aqueous solution and reducing the pressure, and drying the treated wood product. Heretofore, efforts have been made to treat wood in order to achieve various results, including water resistance, mold inhibition, pest (specifically termite) inhibition, and further including a fire retardant. Many different chemicals have been used for these purposes, including silicates, chromium compounds, arsenic based compounds, copper and zinc based formulations, creosote, copper naphthenate, pentachlorophenol and chromate copper arsenate.
U.S. Pat. No. 3,306,765 describes a method for fireproofing wood, which includes the use of an alkali silicate solution together with a borate to impart fire resistant properties to wood, but includes the expensive and environmentally unpopular second step of exposing the treated wood to carbon dioxide at a pressure of about 300 to about 800 p.s.i. to produce polymerization of the silicate/borate combination within the wood. One drawback to this method is that carbon dioxide is considered a greenhouse gas, and releasing large amounts of it in the treatment process could be considered environmentally harmful.
U.S. Pat. No. 6,827,984 is directed to a process of using sodium silicate to create fire retardant products by immersing wood products in a soluble silicate solution, and then drying the wood at elevated temperatures, between 150° C. and 650° C. to cause the silicate solution to become insoluble within the wood.
The use of many of the solutions used for treating wood in the past have certain drawbacks, including the expense of the component products or processes required (including energy usage), the environmental hazards posed, and the safety considerations associated with human contact with such formulations. Further, to date, it has not been possible to provide a single aqueous solution that may be used in standard or pre-existing wood treatment processes that provides a combination of water repellence, fire resistance, mold resistance and pest or termite resistance.
Therefore, it would be desirable to provide a single aqueous wood treatment solution that imparts these characteristics in wood and wood products without using heavy metal compounds, is less expensive to manufacture than existing products, uses lower drying temperatures (and therefore less energy), poses less human safety hazards, and is more environmentally friendly than such existing products and processes.